Companies that use fleets of vehicles are subject to inefficient use and misuse of their fleet vehicles. For example, it is likely that some vehicles in a fleet will be used by employees without authorization. Even employees who are authorized to use a vehicle for some purposes may, in some instances, deviate from an authorized or prescribed route or otherwise make an unauthorized use of the vehicle. Even when vehicles are used for business purposes, the manner of use often results in unnecessary fuel consumption. For example, several maintenance related items, such as driving the vehicle without a properly tuned engine, driving the vehicle with tire pressure outside recommended ranges, and using a grade of motor oil that is not recommended for the vehicle, all contribute to inefficient fuel use, and increased costs. In addition, it is common for a vehicle operator to leave the vehicle idling while making deliveries or performing service, especially in extremes of temperature where the vehicle heater or air-conditioner is used, which contributes to inefficient fuel use. Also, when a vehicle is driven at higher speeds or is driven with a weight load higher than is needed, there is inefficient fuel consumption.
Fuel consumption can also occur at higher levels when the management of a fleet is not done in an efficient manner. For example, vehicle scheduling that does not consider factors affecting fuel economy, such as a schedule that requires a vehicle to make consecutive service stops at opposite ends of a service area when a service stop that is closer is available, can result in higher fuel consumption levels. Similarly, vehicle routing for the vehicle that does not consider factors affecting fuel economy, such as using routes that increase either the time or distance required to be driven between service stops, can also result in higher fuel consumption.
General concepts of how to reduce fuel consumption in individual vehicles are widely known. For example, the U.S. Department of Energy and the U.S. Environmental Protection Agency co-sponsor a website www.fueleconomy.gov that provides tips on improving gas mileage in the areas. These tips are in the areas of driving more efficiently, keeping your car in shape, planning and combining trips and choosing a more efficient vehicle. Examples of the amounts of potential fuel savings obtained from the web-site are given below.
Driving More EfficientlyDriving Sensibly5-33%Observing Speed Limit7-23%Remove Excessive Weight1-2% per 100 lbsKeeping Your Car in ShapeKeeping Vehicle Properly Tuned4%Check and Replace Air Filters RegularlyUp to 10%Keep Tires Properly InflatedUp to 3%Use Recommended Grade of Motor Oil1-2%
Information on reducing fuel consumption by reducing heavy vehicle idling is given at http://www.transportation.ani.gov/research/technologyanalysis/idling.html. Long-haul trucks typically idle 6 hours per day, or 1,830 hours per year, but actual practice varies, from idling 1-2 nights per week to hardly ever turning the engine off. Additionally, each year, about 20 million barrels of diesel fuel are consumed by idling long-haul trucks. Estimated truck emissions total about 10 million tons of CO.sub.2, 50,000 tons of nitrogen oxides, and 2,000 tons of particulates. It is also estimated that the percentage of total fuel saved increases with the number of idling hours avoided.
Additional information on reducing fuel consumption by reducing heavy vehicle idling is given at http://www.cleanairfleets.org/idling.html, where it is stated: “For most on-road, heavy-duty fleets, idling can account for more than 50 percent of total trip time. The amount of diesel fuel burned, the emissions produced, and the maintenance impacts to trucks owners are significant. Consider the following:                A class 8 truck typically idles 8 hours per night, 300 nights per year (2,400 hours per year).        Each year a truck emits over 0.3 tons of nitrogen oxide (NOx) and 21 tons of carbon dioxide (CO2).        A typical diesel vehicle burns one gallon of fuel for every hour of idling.        Idling trucks collectively burn away 1.2 billion gallons of diesel fuel annually at a cost of more than one trillion dollars to the industry.        A truck idling for one hour suffers wear and tear equivalent to being driven seven miles. (ATA Technology and Maintenance Council)        Operating life of engine oil is reduced by 75 percent due to prolonged idling—from 600 engine hours to 150 engine hours.”        
The inefficient use of vehicles therefore results in higher fuel consumption than is needed and results in increased operating costs. One way to reduce these problems is to identify use conditions of vehicles in the fleet that can be modified to reduce fuel consumption.
Numerous methods exist for routing and scheduling the movement of vehicles in a fleet. Such methods can enable a fleet manager to use vehicles in the fleet in an efficient manner, usually related to man-power costs. The addition of fuel consumption determinations to such systems provides opportunities to identify fuel consumption savings.
Accordingly, there is a need for a system and method of identifying modifiable use conditions of vehicles in a fleet that represent a fuel savings opportunity.